ACV depends on inputs the inventory supplies: age, condition, remaining useful life and the replacement cost of a current equivalent. Where those are recorded per item, the adjuster applies the policy. Where they are missing, depreciation gets applied as a blanket percentage across a category, which is rarely accurate and never defensible line by line.
Commercial equipment complicates this further, because well-maintained machinery frequently has more remaining life than its age suggests, and lightly used electronics frequently have less. See RCV and ACV on business personal property.